Extreme Cold Endurance: Wim Hof and the Science
Wim Hof ran a half marathon barefoot above the Arctic Circle and sat in ice for 44 minutes. A 2014 study found his trainees could change their own immune response. Here's what's proven, and the real risks.
As the mornings turn cold, it's a good time to talk about the man who made a career out of being cold on purpose. Wim Hof, nicknamed "The Iceman," has set records in snow and ice that sound impossible. Some of what he claims has held up in the lab. Some of it hasn't been tested, and part of it can be dangerous.
Who he is
Wim Hof was born on April 20, 1959, in Sittard, the Netherlands. He started plunging into cold water as a young man and later built a method around three things: cold exposure, a breathing technique, and commitment.
The feats
- Barefoot half marathon on ice and snow: 2 hours, 16 minutes, 34 seconds, near Oulu, Finland, on January 26, 2007. (The record has since been beaten.)
- Swimming under ice: 57.5 meters in March 2000.
- Full-body ice contact: 44 minutes in January 2010.
- Everest in shorts: in 2007 he climbed to about 6,700 meters (roughly 22,000 feet) wearing very little, before turning back with a foot injury.
- Kilimanjaro: in 2016 he reached Gilman's Point on Kilimanjaro in about 28 hours with a group including journalist Scott Carney.
Several of these records have since been broken by others, which says something too: the human body can be trained to handle more cold than most of us think.
The 2014 study
The most famous science came from Radboud University in the Netherlands. In a 2014 study published in PNAS, researchers led by Matthijs Kox had Hof train 12 healthy young men for 10 days in meditation, his breathing technique, and cold water. Then the volunteers, along with an untrained group, were injected with a bacterial toxin that normally causes flu-like symptoms for a few hours.
The trained group:
- Had much higher adrenaline levels from the breathing.
- Showed more anti-inflammatory and fewer inflammatory signals in their blood.
- Reported fewer flu-like symptoms.
The researchers concluded that people can voluntarily influence a part of the nervous system and immune response once thought to be automatic. It was a small study of young men, and it doesn't prove the method treats any disease.
The risks are real
- Never do the breathing in or near water. The hyperventilation-and-hold breathing can cause a brief blackout. Several practitioners have drowned doing it in pools or open water.
- Cold shock from sudden icy water can trigger gasping and heart rhythm problems. People with heart conditions, high blood pressure, or pregnancy should talk to a doctor first.
- Hypothermia creeps up. Short, supervised exposure is very different from Hof's records.
The safe takeaway
A cool shower, or a short cold rinse at the end of a warm one, is how most people start. The feats belong to someone who has trained for decades. If you want to read about other humans pushing past what seems possible, see Everest without oxygen and the Barkley Marathons.
This article is for general information, not medical advice.
Sources (2)
Kox et al., PNAS 2014: Voluntary activation of the sympathetic nervous system ยท Wikipedia: Wim Hof
Photo: 2019 Wim Hof - by 2eight - DSC6933 by Stefan Brending (2eight), CC BY-SA 3.0 de.